Automatically locking zipper



June 3, 1952 G. SUNDBACK AUTOMATICALLY LOCKING ZIPPER 3 Sheets-Sheet 1 Filed Aug. 8, 1947 ar- 6M attorney June 1952 G. SUNDBACK 2,599,078

AUTOMATICALLY, LOCKING ZIPPER Filed Aug. 8, 1947 3 Sheets-Sheet 2 Zinvcntor Gideon jwfzdback Gttorneg June 3, 1952 G. SUNDBACK 2,599,078

AUTOMATICALLY LOCKING ZIPPER Filed Aug. 8, 1947 3 Sheets-Sheet 5 3k 23 ISmaentor A 9 an Gideon JEzm/aa Gttomeg Patented June 3, 1952 AUTOMATICALLY LOCKING ZIPPER Gideon Sundback, Meadville, Pa., assignor to Talon, Inc., Meadville, Pa., a corporation of Pennsylvania Application August 8, 1947, Serial No. 767,426

8 Claims.

This invention relates to automatic lock zippers. Such zippers have a pair of stringers or rows of interlocking elements, collectively called chain, and a slider embracing the chain for opening and closing the zipper by movement in opposite directions along the chain. The slider is automatically locked to the chain against undesired opening movement but is freely movable to close the zipper. This is accomplished by an automatic lock or pawl, normally pressed against the chain by a spring and shaped to prevent movement of the slider in the opening direction, but permitting dragging or ratcheting of the pawl over the chain whenever the slider moves in the closing direction. The slider has a small handl or pull tab by which it is moved in either direction, and the pull tab automatically lifts the pawl out of engagement with the chain whenever the pull is operated to open the zipper.

While such zippers serve their intended purposes within certain inherent limitations, they have several disadvantages. Since they depend upon the force of the spring to effect looking, a strong spring is required to lock them securely, and this constantly urges the pawl so firmly against the chain that it ratchets roughly over the interlocking elements whenever the zipper is closed. This is objectionably noisy, it makes the slider rough to operate, and the pawl wears on the interlocking elements, rapidly destroying its locking point and destroying the locking action of the slider. When such a lock is used on colored zippers, the locking point rapidly destroys the enamel or chemical finish on the chain. On the other hand, if it is sought to eliminate these disadvantages by using a light spring, uncertainty and insecurity of locking result, and with some types of interlocking elements, positive locking is impossible.

Another objection to previously known lock zippers is that whenever the pawl is holding the zipper locked against a strong opening force (produced by trying to pull the stringers apart) it is diflicult or impossible to unlock the slider and open the zipper by pulling the tab. This may occur, for example, in corsets. This difiiculty is due to two conditions, first the required unlocking movement of the pawl is the direct opposite of its locking movement in the same path, and second the force by which an interlocking element bears on the pawl is substantially perpendicular to this path. Therefore when the forc tending to open the zipper is great, great friction is creor if burrs are present, it may be quite impossible to unlock the zipper by any force which the user can apply to the pull tab with the fingers.

It is among the objects of the present invention to provide an improved form of lock slider in which certainty and security of locking are effected and in which ratcheting of the lock in closing the zipper is eliminated or greatly-reduced; to provide an improved lock slider which is instantly and positively locked upon the slightest tendency toward undesired opening; to provide an improved lock which can be unlocked readily and by slight force even when securely locked against great opening force, and more specifically to provide a locking member which is moved from locked position to unlocked position by a different movement and along a diiferent path than from unlocked position to locked position; and to provide an improved lock which is normally held in a neutral position from which it may be moved automatically either to fully unlocked position when the zipper is intentionally opened, or may be moved to fully locked position by the interlocking elements themselves whenever the zipper tends to open itself.

I have found that in some instances, while it is desirable to accomplish these objects, it may not be desirable to have an absolutely positive lock, for in some uses of the zipper very great and abnormal unintentional opening force on the slider may destroy the zipper or th article to which it is applied. In these instances it is desirable to have a reliable lock having the characteristics of a positive lock against normal opening force, but

' having a safety release which unlocks th zipper when the opening force becomes great enough to cause damage. Accordingly it is another object of my invention to provide an improved slider design by which I can control the point at which the slider will be released without damage, even to the extent of absolutely preventing release where this is desirable.

It is a further object of my invention to provide a lock slider having the characteristics enumerated and which can readily and economically be manufactured.

In the accompanying drawings:

Fig. 1 is a perspective view of on form of zipper embodying my invention;

Fig. 2 is an enlarged section on the plane 2a-2b of Fig. 1 showing the slider lock in neutral position;

Fig, 3 is a fragmentary section corresponding to Fig. 2 showing the slider fully locked;

.Fig. 4 is a view corresponding to Fig. 3 showing the pawl in one fully unlocked position, the position it takes when the zipper is being closed;

Fig. 5 is a view corresponding to Fig. 3 showing the pawl in another fully unlocked position which it takes when the zipper is being opened by the pull tab;

Fig. 6 shows the pawl in a third fully unlocked positionwhich it takes when released by an excessive opening force;

Fig. 7 is a section of the zipper taken on the line 1-1 of Fig. 3;

Fig. 8 is a section corresponding to Fig. Sshowing a modified form of the invention in the fully locked position; and v Fig. 9 is a section corresponding to Fig. 2 showing a second modified form, the pawl being in the neutral position.

Referring to Fig. l, the chain of the zipper has a pair of stringers 20 each consisting of a beaded fabric tape 2] to the beaded edge 22 of which is secured a row. of interlocking elements 23. A slider 24 for opening and closing the zipper has the usual Y-shapedchannel or passage, the end of which is indicated at 25 in Fig. 2 and the cross section of which is indicated at 25 in Fig. 7. The passage surrounds the chain. The passage is" formed by an upper plate 26' of the slider, a lower plate 21 and a wedge 28. The slider, when m ved upward on the chain, that is to the left as seen in Fig. l, progressively interlocks the two rows of elements to close the zipper, and when moved in the opposite direction, progressively disengages the rows to open the zipper. The slider is moved in either direction along the chain by a pull tab or handle 29, slidably securedto' the upper plate by an elongated bail or icon 3Jfa nd so arranged that it can pull the slider from either end'. As' so far described the construction and operation of the z'ipper'a're well known.

the slider exemplifying my invention, the upper plate is provided with an opening 32 (Fig. 2) A look is housed under the loop 38 and arranged so that it can project through the opening32 into the channel 25. Preferably the upper plate has two similar openings 32 and 36 separated by a shelf or bearing 38, as seen best in '7. The locking member consists of a central shaft 43 from which depend a pair of legs 42,,4-3, projecting into the openings. The shaft fills the space between the shelf 33 and the cap or loop 39. It has an opposite pair of rounded faces 44 (Fig. 2') so that it functions as a round shaft, turning through a limited angle in the bearing formed by the'shel'f 33 and the rounded end '45 of a depression 4's in the cap. The shaft can also slide along the shelf 38. The leg 42 forms the active locking pawl, the leg 43 serving to guide the shaft on its bearings and to prevent binding. The side walls 43 (Fig. 7) and the end wall 59' (Fig. 2) of the cap form a well which confines a spring 52 which bears against a flat face 54 of the shaft, urging the shaft to the left against the concave face 45. The end of the spring maybe so formed and positioned that it normally holds the lock with the pawl in the angular position shown in Fig. 2, which is the normal or neutral position of the lock.

The pawl, in its neutral position, is inclined with respect to a line perpendicular to the channel. The pawl is long enough to project slightly into the channel in this position, just enough for the point to contact an interlocking element if the slider moves in either direction. Whenever the lock is in the neutral position, and the slider tends to move in the opening direction without the control of the pull tab, the first interlocking element which contacts the locking point swings the pawl to the left, rotating the shaft clockwise about its center and bringing the pawl into the position (shown in Fig. 3) perpendicular to the channel, causing the locking point to project further into the channel between the interlocking elements. In this position the pawl is stopped or held by the wall of the opening 32, in which position the lock is held by the spring 52, blocking passage of the interlocking elements through the slider, thus preventing movement of the slider to open the zipper.

When it is desired to open the zipper, the pull tab 29 is pulled to the right as seen in Fig. 5. This slides the shaft 49 to the right, compressing the spring. and since the locking point 55 is held by the interlocking element with which it is in contact, the lock rotates clockwise as before, inclining the pawl in the opposite direction to the line which is perpendicular to the rows of elements through the axis of the" shaft as shown inFig. 5, far enough ,to remove the locking point from the path of the'interlocking elements. This permits theslider to be slid to the right and thus to open the zipper.

While the slider cannot be freely moved to open the'zipper except under control of the pull tab, as will be explained,'the slider can be freely moved to close the zipper. Whenever the slider tends to move to the left, as seen in the drawings, each interlocking element strikes against the back of the locking point and rotates the shaft 49 counterclockwise, compress-ing the spring very slightly and'swingin'g the leg 42 into the inclined position shown in Fig. 4, in which the locking point slides over the interlockin elements and permits the slider to move in the closing direction. Since the spring bears against the fiat face 54 the only compression of the spring during this latter rotation is caused by the slight distance that the lower edge of this fiat face moves during rotation of the lock from the position of Fig. 2 to that of Fig. 4. This is a very slight amount and produces a very slight r'estoringforce on the lock, reducing to a minimum the dragging force of the locking point on the interlocking elements when the zipper is being closed, and preventing appreciable wear of the locking point.

It will be observed that in moving into locked position the pawl is rotated clockwise about a fixed pivot remote from the channel, so that its points swings from right to left and in swinging carries itself farther into the channel, until stopped where it projects the maximum distance into the channel. However, in moving to unlocked position the pawl rotates clockwise about the interlocking elements and the formerly fixed pivot is moved laterally to pivot the lock about an interlocking element and swing the opposite end of the pawl from left to right, dragging the pawl out from between the elements. In so doing the'pawl is inclined opposite to the inclination in the neutral position.

As this opposite inclination away from the per pendicular increases, it becomes easier for the force of the interlocking element acting on the locking point to force the locking point out of the channel. This is important in unlocking the slider when it is locked against a very heavy force tending to pull the stringers apart. For, due to the arrangement of the parts, this force tending to open the zipper assists the unlocking inclined face of the locking point 56 to urge the interlocking element against the lower wall 21 of the slider. The wall reacts against the element and causes it to press against the lock in a direction perpendicular to the wall 21, as represented by the force vector 6!. The resultant of these vectors 60 and Bi is the resultant total force exerted by the interlocking element on the locking point. This is represented by the vector 62 which must be perpendicular to the face of the locking point. The component 6| in this position of the lock is perpendicular to the cap and is completely absorbed or opposed by the bottom wall of the depression 44 of the cap. The component 60 is perpendicular to the face of the opening 32 which stops the lock. Thus no movement is produced. However, as soon as the lock is moved by the pull tab slightly away from the perpendicular toward the position of Fig. 5, the component 6| assists in pushin the shaft to the right alon the cap. Increase in the inclination of the leg increases the effectiveness of this component iii in sliding the shaft along the cap, thus the very force which held the lock against its stop can now tend to slide the lock along the stop and along the cap, and assist the pull tab in unlocking the slider.

This condition makes it possible to provide a slider in which the lock is automatically released by being moved away from the positive stop by an excessive force tending to open the zipper without the control of the pull. This is useful, for example, wherever it is desired to have the zipper open without damaging itself at the occurrence of an opening force which would destroy the tape of the zipper or damage the article to which the article is applied.

The component 60 is opposed by an equal force 63 effected by the wall of the opening 32. This force is in the opposite direction to the force 8!,

and it occurs at the point 65 where the lock contacts the stop. If this point is not in line with the force 60, as is indicated in Fig. 5, a couple will be set up tending to rotate the lock clockwise toward the position of Fig. .5'. practical matter, it may be desirable to have some clearance between the inner surface of the top wing and the top face of the interlocking element, there will be some offsetting of the lines of the forces 60 and 63. Thus a couple will be set up which tends to move the lock from the fully locked position to unlocked position. This couple is opposed by the force of the sprin 52 acting at a distance equal to the perpendicular distance from the effective line of action of the spring to the point of contact between the lock and the interlocking element. If the amount of the couple exceeds the moment of the spring, the lock will be rotated clockwise into the position of Fig. 6 and thus be withdrawn from looking position. The moment of the couple, for any given opening force on the slider can be regulated within limits by determiningv the point of contact between the lock and the stop, and

the moment of the spring can be regulated by Since as a changing the force of the spring. Thus, the point at which the safety opening of the zipper occurs can be determined when the slider is constructed.

In some applications of the invention it may be desirable to have clearance between the slider and the interlocking elements and yet have a positive lock which will not be released by any unintended opening force, however great. Such a lock slider is illustrated in Fig. 8. This is constructed as previously described except that the lock has a locking surface 10 which engages a corresponding surface 12 on a relieved portion behind the stop formed by the opening 32. The surface 12 is formed at an angle which will prevent its forming a point bearing for any part of the surface 10. Therefore any tendency of the interlocking element to rotate the pawl out of the perpendicular position and into unlocked position tends to produce clockwise rotation about the edge of the opening 32 at 14. Such clockwise rotation is prevented by the projecting surface lil engaging the surface 12. Preferably the surface 70 is parallel to the inclined face of the locking point 55 and inclined about 45 to the axis of the pawl, and the surface 12 is inclined 45 to the rows of elements, so that 12 is parallel to the face of 56 when the pawl is perpendicular to the rows and in looking position. The surface 10 does not extend toward the interlocking elements beyond the line, perpendicular to the surface 72 and passing through the point of contact between the pawl and an interlocking element. Beyond this line the projection carrying the surface 10 is preferably rounded or relieved on a radius not greater than the distance to the point of contact between the interlocking element and the pawl, so as not to bind when the pull tab, tends to unlock the slider after the manner indicated in Fig. 5. The lock swings clockwise about the interlockin element and the rounded point of the projection carrying the surface 70 clears the surface '12.

In Fig. 9 is illustrated a modified form of the invention in which the spring 52 holds a modified form of lock yieldingly against an inclined stop 90. The locking pin 9! has a head 92 which has a flat side adapted to rest on the sloping surface 90. The spring 52 is placed in a bore or recess 93 and rests in an annular recess 94 surrounding a positioning pin 95 on the head of the lock. The spring substantially fills the bore so as to hold the head againstthe side of the bore, as well as against the inclined stop 90. Otherwise the lock of Fig. 9 operates like that of Figs. 2 to 5, but the inclined stop tends to hold the lock somewhat more positively in its neutral position whenever the slider is not locked nor being either closed or opened by the pull. When the lock rotates from neutral into locked position, it pivots about the fulcrum formed by the edge 96 of the inclined support, this fulcrum being in the line perpendicular to the rows of elements which passes through the stop formed by the wall of the opening 32, insuring that when the lock reaches the stop, it will be perpendicular to the rows of elements and project the maximum distance into the passage.

I claim as my invention:

1. A zipper'comprising in combination a pair of rows of interlocking elements-a slider having a passage for the elements, the passage diverging at one end of the slider and being adapted when moved in one direction along the rows to inter-- lock the rows to.'close the zipperand when moved in the opposite'direction to disengage the rows toopen the zipper, a lock pivoted in the slider and having a locking end, resilient means normally and yieldingly holding the lock in a position with'its axis inclined in one direction away from a line perpendicular to the rows and with its locking and projecting into the path of the elements, a pivot shaft on the look, a pivoting and sliding support for said shaft adapted to maintain the shaft a constant distance from the passage, said resilient means normally holding said pivot shaft on said pivoting and sliding support and the lock being rotatable on said support toward a position perpendicular to the rows to project the locking end further into the path of the elements in response to initial uncontrolled opening movement of the slider, a stop between the ends of the lock for stopping the lock when substantially perpendicular to the rows to prevent further opening movement of the slider, and a second pivot on the lock for contacting the stop.

2. A zipper comprising in combination a pair of rows of interlocking elements, a slider having a passage for the rows and adapted when moved in one direction along the rows to interlock the rows to close the zipper and when moved in the opposite direction'to disengage the rows to open the zipper, a lock in the slider having a locking point at one end and a pivot shaft at the other end, a pivoting and sliding support for the shaft adapted to maintain the shaft a constant distance from the passage, resilient means for yieldingly holding the pivot shaft on said support and the lock normally in a position inclined in one direction to a line perpendicular to the rows with the locking point projecting into the path of the elements, the lock being rotatable in one sense about the axis of the pivot shaft into a position perpendicular to the rows to project the locking point further into the path of the elements, and a stop for stopping the lock in said perpendicular position the zipper including means for rotating the lock in the same sense about the stop into a position inclined in the opposite direction to the perpendicular to remove the locking point from the path of the elements.

3. A zipper comprising in combination a pair of rows of interlocking elements, a slider having a passage for the elements, the passage diverging at one endrof the slider and being adapted when moved in one direction along the rows to interlock the rows to close the zipper and when moved in the opposite direction to disengage the rows to open the zipper, a lock in the slider having a locking end, the lock-being rotatably supported in the slider, resilient means yieldingly holding the lock normally positioned with its axis inclined away from av line perpendicular to the rows and pointing toward the rows and toward the convergent end of the passage and with the locking end projecting into the path of the elements, the lock being rotatable from said inclined position toward said perpendicular, line whereby the lock is adapted to be rotated to project the locking end farther into the path of the elements in response to initial uncontrolled opening movement of the slider, a pivot on the lock between the ends of the lock, a stop on the slider for the pivot for stopping the lock when substantially perpendicular to the rows to prevent further opening movement of the slider, thelock' being adapted to be rotated about the pivot on the stop by excessive force tendin to. move theslider in the opening direction to inclinethelock away from the perpendicular and 8 remove the locking end from the path of the elements.

4. A zipper comprising in combination a pair of rows of interlocking elements, a slider having a passage for the'elements the passage diverging at one end of the slider and being adapted when moved in one direction along the rows to interlock the rows to close the zipper and when moved in the opposite direction to disengage the rows to open the zipper, a lock having a pivot mounted in the slider remote from the rows and having a locking end, resilient means yieldingly holding the lock normally positioned with its axis inclined away from a line perpendicular to the rows and pointing to the rows and to the convergent end of the passage and with its locking end projecting into the path of the elements, the lock being rotatable in one sense about said pivot toward the perpendicular line to project the locking end farther into the path of the elements in response to initial uncontrolled opening movement of the slider, a second pivot on the lock adjacent the rows and a stop on the slider adjacent the passage for stopping the second pivot when the lock is substantially perpendicular to the rows, the lock being rotatable in the same sense about the second pivot on the stop by excessive force tending to move the slider in the opening direction to incline the look away from the perpendicular and to remove the locking end from the path of the elements.

5. A zipper comprising in combination a pair of rows of interlocking elements, a slider havin a passage for the elements, the passage diverging at one end of the slider and being adapted when moved in one direction along the rows to interlock the rows to close the zipper and when moved in the opposite direction to disengage the rows to open the zipper, a lock in the slider having a locking end, resilient means yieldingly holding the lock normally positioned with its axis inclined awayfrom a line perpendicular to the rows and pointing toward the rows and toward the convergent end of the passage and with its locking end projecting into the path of the elements, a pivot shaft on the lock, a pivoting and sliding support for the shaft adapted to maintain the shaft a constant distance from the passage, said resilient means normally holding said pivot shaft on said support the lock being rotatable on said support from said inclined position toward said perpendicular line whereby the lock is adapted to be rotated to project the locking end farther into the path of the elements in response to initial uncontrolled opening movement of the slider, a second pivot on the lock and a stop on the slider between the ends of the lock for stopping the pivot when the lock is substantially perpendicular to the rows, the lock being rotatable and slidable on the second pivot on the stop in response to excessive force tending to move the slider in the opening direction for sliding the shaft along the support to incline the lock in the opposite direction to the perpendicular and to remove the locking end from the path of the elements.

6. A zipper comprising in combination a pair of rows of interlocking elements, a slider having a passage for the elements and adapted when locking point at one end and a pivot shaft at the other end, a pivoting and sliding support for the shaft in the slider adapted to maintain theshaft a constant distance from the passage, resilient means yieldingly holding the pivot shaft on said support with the lock in a position normally inclined in one direction with respect to a line perpendicular to the rows and having the locking point projecting into the path of the elements, the lock being rotatable in one sense about the pivot support into a position perpendicular to the rows to project the'locking point farther into the path of the elements, means on the slider for stopping the lock substantially perpendicular to the rows, the lock being rotatable in the same sense about the stopping means to a position inclined in the opposite direction to the perpendicular to remove the locking point from the path of the elements.

7. A zipper comprising in combination a pair of rows of interlocking elements, a slider having a passage for the elements, the passage diverging at one end of the slider and being adapted when moved in one direction along the rows to interlock the rows to close the zipper and when moved in the opposite direction along the rows to disengage the rows to open the zipper, a locking member in the slider resilient means yieldingly holding the locking member in a position normally inclined to a line perpendicular to the rows and pointing toward the rows and toward the convergent end of the passage, a locking point on the locking member, a pivot on the locking member remote from the passage, a pivoting and sliding support on the slider for said pivot, said resilient means yieldingly holding said pivot on said support the locking member being rotatable in one direction about the pivot to move the locking member toward said perpendicular line and to move the locking point toward the center of the passage and between the interlocking elements, a bearing surface on the locking member adjacent the looking point adapted to contact an interlocking element when the locking point is so placed between the interlocking elements, a stop on the slider adapted to contact the look at a point spaced axially from said bearing surface when the lock is substantially perpendicular to the rows whereby opening force on the slider sets up a couple on the lock between the bearing surface and the stop, said couple tending to rotate the lock in the opposite direction away from said perpendicular line. q

8. A zipper comprising in combination a pair of rows of interlocking elements, a slider having a passage for the rows, the passage diverging at one end of the slider and being adapted when moved in one direction along the rows to interlock the rows to open the zipper and when moved in the opposite direction along the rows to disengage the rows to open the zipper, a locking member on the slider having a locking end, resilient means yieldingly holding said locking member normally positioned with its axis inclined away from a line perpendicular to the rows and pointing toward the rows and toward the convergent end of the passage and with the locking end projecting into the path of the elements, a pivot shaft on the locking member, a pivoting and sliding support for said shaft adapted to maintain the shaft a constant distance from the passage, said resilient means yieldingly holding said pivot shaft on said support the locking member being rotatable on said support toward said perpendicular line to project the locking end farther into the path of the elements in response to initial uncontrolled opening movement of the slider, a stop on the slider for stop-ping the look when its axis is substantially perpendicular to the rows, the zipper including means for sliding and rotating the shaft on the support to incline the lock in the opposite direction away from said perpendicular line and thus to remove the locking end from the path of the elements.

GIDEON SUNDBACK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,222,988 Poux Nov. 26, 1940 2,271,141 Lange Jan. 27, 1942 2,289,585 Marinsky July 14, 1942 2,301,792 Plumley Nov. 10, 1942 FOREIGN PATENTS Number Country Date 417,781 Great Britain of 1934 512,643 Great Britain of 1939 

